*ngFor='let unit of boardState; slice: 0: 3; let i=index' code example
Example: ngfor limit to 10
<li *ngFor="let item of list | slice:0:10; let i=index" class="dropdown-item" (click)="onClick(item)">{{item.text}}</li>
<li *ngFor="let item of list | slice:0:10; let i=index" class="dropdown-item" (click)="onClick(item)">{{item.text}}</li>